Studies will be continued of the synthesis, processing and sequence of the rat growth hormone precursor, pregrowth hormone. The rat growth hormone gene sequence insert present in a recombinant bacterial plasmid which we have recently constructed will be characterized. This plasmid will also be employed as a molecular hybridization probe in studies of the regulation by glucocorticoid and thyroid hormones of the transcription of the growth hormone gene and the processing of the initial transcript in clonal lines of rat pituitary tumor cells.